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How Much Caffeine Before a Workout?

Enter your body weight to see the caffeine range sports research has studied, which of the drinks we track fall inside it, and how much will still be in your system at bedtime. Every figure comes from the sources listed at the bottom.

A research summary, not medical advice. If you have a health condition, take medication, or are unsure, ask a doctor first.

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What the research says

  • The studied range is 3–6 mg per kg of body weight. That's where performance benefits showed up consistently, and some studies found an effect from as little as 2 mg/kg. Very high doses, around 9 mg/kg, came with a high rate of side effects.[1]
  • It helps endurance and speed more than your max. Across meta-analyses, caffeine gave a small boost to strength (effect 0.18) and a slightly larger one to muscular endurance, meaning more reps (0.30), with bigger effects at 5 mg/kg or more.[2] In resistance training, bar speed improved more (0.42) than power output (0.21).[3]
  • Regular caffeine users may get less out of it. The bar-speed effect was larger in people with low day-to-day caffeine intake.[3] People also respond differently because of genetics: in one study, the same 4 mg/kg dose helped fast caffeine metabolizers and hurt slow ones.[1]
  • Beginners benefit too. Benefits showed up in both trained and untrained people.[1] Women saw a slightly larger strength effect than the combined groups.[2]
  • Timing matters. Most studies gave caffeine about 60 minutes before exercise.[1] It peaks in the blood 30 minutes to 2 hours after drinking, and half of it is typically gone after 3–6 hours.[5] Athletes who took it before evening training reported noticeably worse sleep.[4]

Limits worth knowing

  • Up to 400mg a day, from all sources combined, is the FDA's figure for healthy adults.[6] EFSA found single doses up to 200mg raised no safety concerns, including within 2 hours before intense exercise under normal conditions.[7] This page never lists a drink above 400mg.
  • Children and teens: the American Academy of Pediatrics says energy drinks should not be consumed at all.[8]
  • Pregnancy: ACOG advises keeping caffeine under 200mg a day.[9]
  • Count everything: coffee, tea, pre-workout powders and energy drinks all add up toward the daily total.

Common questions

How much caffeine should I have before a workout?
Sports research (ISSN, 2021) consistently found benefits at 3–6 mg of caffeine per kilogram of body weight, with some benefit from as little as 2 mg/kg. For a 175 lb (79 kg) adult that is about 240–475 mg. The FDA's guideline for healthy adults is up to 400 mg a day from all sources combined, and very high doses (around 9 mg/kg) mostly add side effects.
Does caffeine help you lift more?
A little. A 2024 meta-analysis of meta-analyses found a small improvement in muscular strength (standardized effect 0.18) and a slightly larger one in muscular endurance (0.30), with bigger effects at 5 mg/kg or more. A 2025 meta-analysis found larger gains in bar speed (0.42) than in power output (0.21), and bigger effects in people who don't use much caffeine day to day.
When should I drink a pre-workout before training?
Studies most often gave caffeine about 60 minutes before exercise. Caffeine reaches its peak in the blood roughly 30 minutes to 2 hours after drinking it.
Will a pre-workout drink in the evening affect my sleep?
It can. Caffeine's half-life averages about 3–6 hours and ranges from roughly 2 to 10 hours between people. A 2025 review of athletes who took caffeine before evening training found they consistently reported worse sleep, and suggested stopping 4–6 hours before bedtime.

Looking for drinks with pre-workout ingredients like citrulline or beta-alanine? See the pre-workout drink rankings, or compare every drink by caffeine.

Sources

  1. [1] Guest NS et al. ISSN position stand: caffeine and exercise performance. J Int Soc Sports Nutr, 2021.
  2. [2] Bilondi HT et al. Caffeine supplementation on muscular strength and endurance: a meta-analysis of meta-analyses. Heliyon, 2024.
  3. [3] Xiao Y et al. Acute caffeine intake and muscular power during resistance exercise: a meta-analysis. Frontiers in Nutrition, 2025.
  4. [4] Kocak A et al. Caffeine before late afternoon/evening training and sleep: a systematic review with meta-analysis. Sports, 2025.
  5. [5] Willson C. The clinical toxicology of caffeine: a review and case study. Toxicology Reports, 2018.
  6. [6] U.S. FDA. Spilling the Beans: How Much Caffeine Is Too Much?
  7. [7] EFSA. Scientific Opinion on the safety of caffeine. EFSA Journal, 2015.
  8. [8] American Academy of Pediatrics. Sports drinks and energy drinks for children and adolescents. Pediatrics, 2011.
  9. [9] ACOG Committee Opinion No. 462: Moderate caffeine consumption during pregnancy.